The field of the invention is laboratory evaluation apparatus and the invention relates more specifically to devices useful in viewing liquid specimens under a microscope. This field has become highly developed for several specific techniques applicable to the present invention. The most common of which is a microscopic evaluation of the urine sediment.
A highly reproducible system for microscopic evaluation of sediment is disclosed in applicant's U.S. Pat. No. 3,777,283, which discloses a microscopic slide having a plurality of transparent viewing areas. The viewing areas are loaded by placing liquid on a platform that communicates with the viewing area. The liquid is then drawn into the viewing area by capillary action and is held to the desired predetermined thickness for optimum viewing.
Other liquid viewing devices are also disclosed in the prior art. One such device is shown in the Fielding U.S. Pat. No. 3,565,537, which shows a specimen holder useful for the optical evaluation of samples of blood. The Lilja U.S. Pat. No. 4,088,448, discloses a device for taking samples which may be transparent and which draws the sample into the device by capillary action. A blood sample holder is shown in U.S. Pat. No. 3,198,064 to Moore and discloses a pair of parallel plates which hold the sample in a film of a predetermined thickness. A liquid inspection slide is shown in U.S. Pat. No. 3,961,346 to White and, like applicants earlier mentioned patent has a plurality of transparent viewing areas loaded from a platform.
Outside of the medical field a liquid sampling and viewing device is shown in a patent to Johnson U.S. Pat. No. 3,905,702 which provides a thin film of oil formed by capillary action in a transparent viewing chamber so that the solid contaminents in the oil may be viewed. The opacity of the oil may be observed by the unaided eye.
With further sophistication and urinalysis techniques there has been an increasing tenancy toward the use of pipettes and disposable pipettes such as that shown in U.S. Pat. No. 4,022,576 to Parker are widely used. This facilitates the transfer of the sample from the test tube to the microscopic slide. Because of the ease of use of such pipettes it is appropriate that microscopic slides be developed which take advantage of the capabilities of such pipettes.